The Immune System

The Immune System

What is the immune system?

The
immune system protects your child’s body from outside invaders. These include germs
(such as bacteria, viruses, and fungi) and toxins (chemicals made by microbes). The
immune system is made up of different organs, cells, and proteins that work
together.



There are 2 main parts of the immune system:

  • The innate immune system. You are born with
    this.

  • The adaptive immune system. You develop this
    when your body is exposed to microbes or chemicals released by microbes.

These 2 immune systems work together.

The innate immune system

This is your child’s rapid response system. It is the first to respond when it finds
an invader. It is made up of the skin, the eye’s cornea, and the mucous membrane that
lines the respiratory, gastrointestinal, and genitourinary tracts. These all create
physical barriers to help protect your child’s body. They protect against harmful
germs, parasites (such as worms), or cells (such as cancer). The innate immune system
is inherited. It is active from the moment your child is born. When this system
recognizes an invader, it goes into action right away. The cells of this immune
system surround and cover the invader. The invader is killed inside the immune system
cells (called phagocytes).

The acquired immune system

The acquired immune system, with help from the innate system, makes cells
(antibodies) to protect your body from a specific invader. These antibodies are
developed by cells called B lymphocytes after the body has been exposed to the
invader. The antibodies stay in your child’s body. It can take several days for
antibodies to form. But after the first exposure, the immune system will recognize
the invader and defend against it. The acquired immune system changes during your
child’s life. Immunizations train your child’s immune system to make antibodies to
protect him or her from harmful diseases.

The cells of both parts of the immune system are made in different organs of the
body, including:

  • Adenoids. Two glands located at the back of the nasal passage.

  • Bone marrow. The soft, spongy tissue found in bone cavities.

  • Lymph nodes. Small organs shaped like beans, which are located all over
    the body and connect via the lymphatic vessels.

  • Lymphatic vessels. A network of channels all over the body that carries
    lymphocytes to the lymphoid organs and bloodstream.

  • Peyer’s patches. Lymphoid tissue in the small intestine.

  • Spleen. A fist-sized organ located in the belly (abdominal) cavity.

  • Thymus. Two lobes that join in front of the windpipe (trachea) behind
    the breastbone.

  • Tonsils. Two oval masses in the back of the throat.

How do antibiotics help fight infections?

Antibiotics can be used to help your child’s immune system fight infections by
bacteria. But antibiotics don’t work for infections caused by viruses. Antibiotics were
developed to kill or disable certain bacteria. That means that an antibiotic that works
for a skin infection may not work to cure diarrhea caused by bacteria. Using antibiotics
for viral infections or using the wrong antibiotic to treat a bacterial infection can
help bacteria become resistant to the antibiotic so it won’t work as well in the
future. It’s important to take antibiotics as prescribed and for the right amount of
time. If antibiotics are stopped early, the bacteria may develop a resistance to the
antibiotics. Then the infection may come back again.

Most
colds and acute bronchitis infections won’t respond to antibiotics. You can help
decrease the spread of more aggressive bacteria by not asking your child’s healthcare
provider for antibiotics in these cases.